The Raspberry Pi 5 is running a binary distribution of Debian GNU/Linux on Raspberry
Pi 5 as found at https://www.raspberrypi.com/software/operating-systems/#raspberry-pi-os-64-bit
(Raspberry Pi OS Lite, Release date: November 19th 2024 based on Debian version: 12 (bookworm)
and a kernel 6.6 -- Linux raspberrypi 6.6.74+rpt-rpi-2712 #1 SMP PREEMPT Debian 1:6.6.74-1+rpt1 (2025-01-27) aarch64 GNU/Linux) but using the kernel8.img kernel rather than the default
(see the config.txt line stating kernel=kernel8.img) to use 4 KB memory pagesize rather
than the defaut 16 KB on RPi5.
The XTRX is fitted on the PCI bus using https://pineboards.io/products/hat-mpcie-for-raspberry-pi-5.
Make sure that
$ lspci
0000:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries BCM2712 PCIe Bridge (rev 21)
0000:01:00.0 Memory controller: Xilinx Corporation Device 7012
0001:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries BCM2712 PCIe Bridge (rev 21)
0001:01:00.0 Ethernet controller: Raspberry Pi Ltd RP1 PCIe 2.0 South Bridge
i.e. the XTRX is visible with the Xilinx Corporation Device 7012. In case this entry
is not visible, either check the XTRX connection, or reboot (seems that the board is not
always detected on the PCI bus).
In the XTRX driver,
comment the #ifdef ... statement to set #define VA_DMA_ADDR_FIXUP (around line 180)
-#ifdef CONFIG_CPU_RK3399
+//#ifdef CONFIG_CPU_RK3399
#define VA_DMA_ADDR_FIXUP
-#endif
and replace
pbufs[i].virt = dma_alloc_coherent(&d->pdev->dev, buflen, &pbufs[i].phys, GFP_KERNEL);
with
pbufs[i].virt = dmam_alloc_coherent(&d->pdev->dev, buflen, &pbufs[i].phys, GFP_KERNEL);
(notice the dmam instead of dma -- see https://github.com/enjoy-digital/litex_xtrx/blob/master/software/kernel/main.c#L171 for the inspiration of this correction by Gwen Goavec-Merou).
This procedure is automated with
git clone https://github.com/xtrx-sdr/xtrx_linux_pcie_drv
cd xtrx_linux_pcie_drv
git checkout d218d3e8be3f723000bdfff6b6235a85f7b10e42
patch -p1 < ../xtrx.patch
After compiling this modified kernel and loading to memory from the xtrx_linux_pcie_drv
directory
make
sudo insmod xtrx.ko
sudo dmesg
(be aware that rmmod xtrx with kernel panic) leads to
...
[ 108.790866] xtrx: buf[31]=2b08000 [virt 00000000a5952f9b] => 02b087ff
[ 108.790985] xtrx: Port config: 0 (1)
[ 108.790987] xtrx: Port request: 0
[ 108.790990] 0000:01:00.0: ttyXTRX0 at MMIO 0x0 (irq = 0, base_baud = 9600) is a xtrx_uart
[ 108.791110] xtrx: Port config: 1 (1)
[ 108.791112] xtrx: Port request: 1
[ 108.791113] 0000:01:00.0: ttyXTRX1 at MMIO 0x0 (irq = 0, base_baud = 9600) is a xtrx_uart
[ 108.791116] xtrx: SIM mctrl=0
and indeed ls -l /dev/xtrx* must display one entry.
The Osmocom source requires the argument args="xtrx,dev=/dev/xtrx0" to run with the XTRX.
Executing the resulting Python script leads to:
./testxtrx.py
gr-osmosdr 0.2.0.0 (0.2.0) gnuradio 3.10.11.0
built-in source types: file fcd rtl rtl_tcp uhd miri hackrf bladerf rfspace airspy airspyhf soapy redpitaya freesrp xtrx
xtrx,dev=/dev/xtrx0
xtrx_source_c: XTRX device: %s/dev/xtrx0xtrx_obj::xtrx_obj = 4
06:42:27.883905 INFO: [XTRX] xtrx_open(): dev[0]='/dev/xtrx0'
06:42:27.883937 INFO: [ DEF] Probing 'libxtrxll_pcie.so.0' low-level library
06:42:27.886356 INFO: [ DEF] Probing 'libxtrxll_libusb3380.so.0' low-level library
...
06:42:28.189733 INFO: [BPCI] PCI:/dev/xtrx0: RX DMA 16 bit SISO (BLK:16384 TS:262144); TX DMA SKIP MIMO @0.0
06:42:28.189769 INFO: [CTRL] PCI:/dev/xtrx0: Placing TC @262144 on 0 data: 0 stat:20
06:42:28.189853 INFO: [LMSF] PCI:/dev/xtrx0: NCO ch=3 type=3 freq=0
Press Enter to quit: Using generic for xtrxdsp_iq16_sc32
and playing on a PC the resulting audio file sounds functional (mplayer xtrx.wav).